The seven-month contract for the rehabilitation of a section of the N2 freeway, near Durban, was completed on schedule and within budget during December 2003, UWP Consulting reported.

UWP was appointed by the South African National Roads Agency (Sanral), in June 2002, to investigate and avail recommendations for the rehabilitation of a 20-km section of the four-lane dual carriageway freeway between the Ilovo River and the Mlaas Canal (past the Durban International Airport), south of Durban. A comprehensive assessment was conducted, which included a detailed visual assessment, material testing and surface deflection analysis.

Based on the assessment, UWP’s rehabilitation experts, Mike White and Renaldo Lorio, reported that the road was generally sound and that the defects were mainly confined to the existing wearing course layer.

It was, therefore, recommended that the existing wearing be removed in the distressed areas and replaced with new asphalt. It was further recommended that the serious cracks be sealed and that a new asphalt overlay be constructed after the completion of the preparatory work.

Murray & Roberts Roads and Earthworks were appointed by Sanral after an open tender procedure. As part of their tender, they offered their proprietary hot-mix asphalt overlay material (Novachip) as an alternative to the recommended stone mastic asphalt (SMA). "This alternative was accepted by Sanral as the same benefits could be achieved at a lower cost. Novachip material is laid 20 mm thick as opposed to the 30 mm required for SMA," said Ron Isaac, UWP’s project manager.

"The two important considerations for this project were to prevent an increase of traffic-related noise subsequent to construction, as this section of the N2 passes through the residential areas of Amanzimtoti and Kingsway. Construction efficiency was also paramount due to restricted working hours which were enforced on this heavily trafficked freeway," he concluded.